This IS the "other hardware" party of the forum, though usually we prefer topics to be somewhat Arduino-related...You could in fact replace the entire circuit up to the ULN chips with an Arduino or AVR chip, simultaneously gaining the ability to operate via USB (and/or get debugging info via USB.)

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it doesn't run when we provide the voltage

"doesn't run" how? What are you doing to it, and how are you expecting it to behave?

You have no bypass caps.The 74LS05 has open-collector outputs and really isn't well-suited to use as a general purpose inverter. Though it might work if you're using "real" 74ls series logic, since inputs float high.It looks like the circuit should toggle the relays when you provide a clock by select/deselect/etc the inputs to the '154, but your circuit isn't providing any toggling. Doing so by attach/detach of wires will have "bounce" issues.

(um, are you working from here: http://xman.postalboard.com/t75-device-switching-using-pcs-parallel-port ?Or a less detailed source of information? Maybe their explanation will help (but it doesn't look like a very good explanation to me.)

This IS the "other hardware" party of the forum, though usually we prefer topics to be somewhat Arduino-related...You could in fact replace the entire circuit up to the ULN chips with an Arduino or AVR chip, simultaneously gaining the ability to operate via USB (and/or get debugging info via USB.)

Quote

it doesn't run when we provide the voltage

"doesn't run" how? What are you doing to it, and how are you expecting it to behave?

You have no bypass caps.The 74LS05 has open-collector outputs and really isn't well-suited to use as a general purpose inverter. Though it might work if you're using "real" 74ls series logic, since inputs float high.It looks like the circuit should toggle the relays when you provide a clock by select/deselect/etc the inputs to the '154, but your circuit isn't providing any toggling. Doing so by attach/detach of wires will have "bounce" issues.

Yes when provide 12v to relay and 5v to other chips that in the circuit diagram The fan doesn't work

Kinda tough to see what is going on there since there aren't any labels or schematics. Without knowing the circuit or having some idea of what you want it to do it's going to be hard to help out, especially with "code" for hardware you might not be using. Is this going to be connected to an Arduino at some point?

Also, this is the "Other Software Development" board; you might have better luck posting in "General Electronics" or (if you're going to use an Arduino) "Interfacing w/ Software".